Income Tax Expense (Detail) ₨ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2017 INR (₨)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 INR (₨)	Mar. 31, 2015 INR (₨)
Components of Income Tax Expense Benefit Abstract
Current income tax expense	₨ 84,273.5	$ 1,299.6	₨ 68,947.3	₨ 54,954.4
Deferred income tax (benefit) expense	(5,048.6)	(77.9)	(1,410.4)	(352.1)
Interest on income tax refund	0.0	0.0	0.0	(82.4)
Income tax expense	₨ 79,224.9	$ 1,221.7	₨ 67,536.9	₨ 54,519.9

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.7)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration